Lamb wave mode-conversion based biological stimulation device

Abstract

Ultrasonic excitation to a sample is provided with an apparatus including: a cylindrical ultrasonic transducer, and a plate disposed on an end of the cylindrical ultrasonic transducer. The ultrasonic transducer is configured to provide a vertical vibration in operation. A Lamb wave vibration is generated in the plate by the vertical vibration of the ultrasonic transducer. The Lamb wave vibration converges at a central region of the plate, where a sample is disposed. Alternatively, a cylindrical array of ultrasonic transducers can be used instead of a single cylindrical transducer. Such an array can be driven as a phased array for beam shaping and/or multi-focusing.

The invention claimed is: 
     
         1 . An apparatus for providing an ultrasonic excitation to a sample, the apparatus comprising:
 a cylindrical ultrasonic transducer;   a plate disposed on an end of the cylindrical ultrasonic transducer;   wherein the ultrasonic transducer is configured to provide a vertical vibration in operation;   wherein a Lamb wave vibration is generated in the plate by the vertical vibration of the ultrasonic transducer;   wherein the Lamb wave vibration converges at a central region of the plate, and wherein a sample is disposed at the central region of the plate.   
     
     
         2 . The apparatus of  claim 1 , wherein a propagation speed of the Lamb wave vibration in the plate is less than a speed of sound in the sample. 
     
     
         3 . The apparatus of  claim 1 , further comprising a sample holder configured to hold the sample in place at the central region of the plate. 
     
     
         4 . An apparatus for providing an ultrasonic excitation to a sample, the apparatus comprising:
 two or more transducers configured as a cylindrical array;   a plate disposed on an end of the cylindrical array;   wherein the two or more ultrasonic transducers are configured to provide a vertical vibration in operation;   wherein a Lamb wave vibration is generated in the plate by the vertical vibration of the two or more ultrasonic transducers;   wherein the Lamb wave vibration converges at a central region of the plate, and wherein a sample is disposed at the central region of the plate.   
     
     
         5 . The apparatus of  claim 4 , wherein a propagation speed of the Lamb wave vibration in the plate is less than a speed of sound in the sample. 
     
     
         6 . The apparatus of  claim 4 , further comprising a sample holder configured to hold the sample in place at the central region of the plate. 
     
     
         7 . The apparatus of  claim 4 , further comprising a controller configured to provide phased-array excitation of the two or more ultrasonic transducers. 
     
     
         8 . The apparatus of  claim 7 , wherein the phased-array excitation of the two or more ultrasonic transducers is configured to provide multifocal excitation to the sample.